Spinal Cord Morphology - S Flashcards
What and where is the cauda equina?
Formed by the dorsal and ventral roots (some of which come from the conus medullaris) that course through the lumbar cistern before exiting at respective levels
What is the lumbar cistern?
Expansion of the subarachnoid space from the conus medullaris to the end of the dural sac at S2
Name the spinal cord segment applied to the sensory dermatomes: shoulder, thumb (Pollicis), little finger/elbow, nipple, umbilicus, inguinal region, big toe (Hallucis), little toe, perianal region
C4, C6, T1, T4, T10, L1, L5, S1, S5
Name the spinal cord segments in relation to the motor dermatomes for: biceps, brachialis, triceps, muscles of the hand, quadriceps femoris, gastrocnemius.
C5-6, C6-7, C6-8, C8-T1, L2-4, L5-S2
What levels of the SC are most prone to ischemic events?
Upper levels of C, T, and L (all of which are the SC enlargements)
What a supplies the inerior 2/3rds of the SC? What does it contribute to? When can it be compromised? When blocked or damaged, what sx follow?
Great Anterior Artery of Adamkiewicz, contributes to the anterior spinal a
Thoracolumbar fracture, surgery for an abdominal aortic aneurysm (AAA)
Paraplegia w/o sexual function, depression
Disruption of what leads to central cord syndrome?
Anterior Spinal
What a supplies most of the blood to the posterior columns?
Posterior spinal aa
What is the venous drainage for the SC?
Internal venous plexus of Batson
What does the gamma efferent motor pathway drive? What does a tighter spindle mean? What does being anxious do?
Intrinsic intrafusal fibers of the muscle spindles for proprioception and muscle tone
Increased tone and increased sensitivity to stretch (hypertonia and hyperreflexia)
Increases spindle tightness/tone and reflex briskness
What neurons are also considered LMNs?
Alpha and gamma motor neurons
What is essential for proper performance of precise muscle patterns?
Optimal muscle tone set by gamma motor neurons (not too much and not too little/hyper or hypotonia)
What is the phrenic nucleus a subdivision of?
The MMCC
What does the intermediolateral nucleus do?
Sends preganglionic symp fibers to visceral structures
What does the sacral autonomic nucleus do?
Preganglionic parasymp fibers to the bowels and bladder
What is the fasciculus proprius?
Has LRST embedded in it which conducts slow pain, the “beach” of the gray matter, primitive reticular formation, diffuse fibers of slow pain tract reason why lesions of these fibers are unlikely to solve clinical issues (or cause them)
What do spinoreticular fibers do?
Convey slow and visceral pain sensations to the ascending reticular activating system (ARAS)
What do the DSCT and VSCT do and where?
They relay unconscious, precise proprioceptive information
DSCT does it for the LE’s and VSCT does it for the UE’s
Where does the Rubrospinal Tract originate from?
The Red Nucleus in the mesencephalon
What and where is the conus medullaris? What does it contain?
The tapered end of the SC in the lumbar region o L-L2
Contains extending nerve rootlets that innervate the lower sacral dermatomes, bladder, and rectum
